1. Field of the Invention
The present invention relates to a sample introduction system.
2. Discussion of the Prior Art
Conventional approaches to quantifying the unknown concentration of one or more analytes of interest in a sample using an analytical instrument such as a mass spectrometer (especially Inductively Coupled Plasma (“ICP”) mass spectrometers) rely upon having first calibrated the analytical instrument using different strength calibration solutions of an analyte(s) of interest. These calibration solutions are individually prepared off-line which is time consuming and may potentially give rise to inaccuracies. Once the analytical instrument has been calibrated then the concentration of one or more analytes of interest in a sample can be determined by measuring the response of the analytical instrument and comparing the measured response with a calibration curve obtained from measuring the response of the analytical instrument to the various calibration solutions.
The conventional approach is prone to suffering from variations in response due to either differences between the sample matrix and the calibration standards, instrumental drift or combination of the two. These variations in response can be particularly acute with ICP mass spectrometers and therefore being able to determine accurately the concentration of an analyte in an analytical instrument such as an ICP mass spectrometer is a non-trivial matter.
It is therefore desired to be provide an improved method and apparatus for determining the concentration of an analyte(s) in a sample.